IPTV (Internet Protocol TeleVision) architectures have been developed to provide services over IP networks including multicast digital television, video on demand (VoD), television on demand (Catch-up TV or TVoD), and digital video recorder functions activated on television or video streams such as NPVR (Network-based Personal Video Recorders) or real time live TV stream control (Network-based Time Shifting (NTS), also known as Pause Live TV). Such architectures use streaming and multicast mechanisms.
A streaming or point-to-point mechanism transports a data stream from a source to a destination continuously, the stream being processed on the fly at the destination without having to store it in its entirety.
In an IPTV architecture, a stream consists of a series of IP packets transporting an audiovisual content. These packets are sent by the source in the same chronological order as the multimedia data that they transport.
A multicast or point-to-multipoint mode of broadcasting over a transport network organizes and optimizes sending the same data stream from a source to a plurality of destinations.
At present, most audiovisual stream transport systems are based on encapsulation standards close to the DVB (Digital Video Broadcasting) standard and the MPEG (Motion Picture Experts Group) audiovisual content coding standard. Those standards propose various protocols for encapsulating the audiovisual streams in order to transport them in fixed and mobile IP networks.
Transporting audiovisual streams requires a high bandwidth. The use of an IPTV service therefore makes it necessary to size and plan the network accordingly and to distribute network resources between subscribers to the service.
At present there exist as many cohabiting IPTV architectures as there are different types of user terminal and access network. An IPTV service can be accessed from a television or a PC via a WiMAX or xDSL (Digital Subscriber Line) fixed IP access network or from a mobile telephone via a 3G UMTS (Third Generation Universal Mobile Telecommunications system) mobile IP access network. The various offers (via TV, PC, or mobile telephone) are at present independent. This multiplicity of infrastructures (mobiles, fixed, even IPTV, and Internet TV) leads to a situation that is hardly the optimum in terms of deployment and maintenance costs, consumption of network bandwidth, and storage on the installed base of content servers. Moreover, there is only very limited interaction between services offered in the mobile world and those offered in the fixed world.
Moreover, it should be noted that, in a fixed service (xDSL) context, the cohabitation of TV-HD and TV-SD offers at present requires the simultaneous transporting of HD (high definition) and SD (standard definition) versions of the same audiovisual content on the various network segments (backbone and collection) and as far as the first DSL collection node or DSLAM (Digital Subscriber Line Access Multiplexer).
The situation will be exactly the same if the IPTV service is widened to mobile terminals, for which one or more additional versions of the audiovisual content will have to be produced, stored, and transported to enable the user to access content interchangeably from a fixed access point (WiMAX, WiFi Hotspot) or from a mobile access point (3G UMTS).
In a fixed service (xDSL) context, the ability of the subscriber to access one or more audiovisual services is set up and then configured statically in the network. This solution is highly inflexible. It does not estimate the available network resource at a given time or adapt audiovisual content distribution conditions dynamically as a function of the resources available to optimize the cohabitation of multimedia (audiovisual, conversational, Internet, etc.) services, possibly between a plurality of users connected to the same access point.
There is therefore a need to alleviate these drawbacks of the prior art in order to provide a better response to the expectations of users.
To be more precise, there is a need for a solution that dynamically adapts audiovisual content distribution conditions as a function of the resources available on a link between a network entity and a user terminal's network access point.
There is also a need to manage a plurality of multimedia sessions in parallel, whether of audiovisual, conversational, or other type.
There is further a need to optimize the sharing of resources on a given link between a plurality of multimedia sessions based on dynamic management of the available resources.
There is a yet further need for a multimedia session management architecture capable of managing all types of multimedia session, regardless of the access network from which they come or the type of terminal that requested them.